methyl group rotation averaging

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andysardjan
Newbie
Posts: 1
Joined: Tue Feb 02, 2021 8:10 am

methyl group rotation averaging

Post by andysardjan »

Hi,

I did calculations on different conformers of organic molecules to predict their EPR spectra (using ORCA). For most molecules I get good agreement, however with some molecules less so. However in those molecules the radical center is next to a methyl group. I guess easyspin does not take rotation of this methyl group into account. I tried to search this forum (and the orca forum) to find implemented methods to take this into account. If it was one molecule i could do this 'by hand', however since i have many conformers i am searching for an automated way to average these hfc's.

The problem lies with importing the data from orca to easyspin, as i have done the calculation with the output of all hfc's i have to use a cuttoff in orca2easyspin(). However because of this function, I do not know anymore which is of nuclei are in this methyl group and in some conformers I have all three protons within the cuttoff and sometimes only a two. So is there an automated way of taking methyl rotation into account? Or is there a way to edit the .prop files so that i can set the methyl's hfc's to the average number.

Best regards and thanks in advance,
Andy Sardjan

Stefan Stoll
EasySpin Creator
Posts: 1053
Joined: Mon Jul 21, 2014 10:11 pm
Location: University of Washington

Re: methyl group rotation averaging

Post by Stefan Stoll »

Unfortunately, neither is possible. I suggest importing all the nuclei of the spin system, then identifying which ones are the methyl protons, and then replacing their hyperfine values with their average.

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